Bradley Cooper knows how to work a talk-show audience—and apparently Washington, D.C., movers and shakers.

The "American Hustle" actor admitted to Ellen DeGeneres that he went commando during the recent White House State Dinner—much to the delight of her studio audience.

Cooper explained that he has gained so much weight for a new movie that "nothing fits me anymore."

"I wore the tuxedo I wore to the Golden Globes. I just sort of threw it in the bag, and brought it and went to Washington, D.C. I’m getting dressed 10 minutes before I’m supposed to go."

"Literally, the pants go up to here," he said, gesturing to his upper thigh. "I just started laughing actually, 'This is hilarious ...' So I had to go commando, No. 1, because there was no room at all. I did. I had to."

As you can see in the video above, Cooper had to find a non-exposing way to meet all the politicos, military commanders and other guests at the Feb. 11 dinner.